Abstract

BaTiO3 films are extensively used in many electrical devices, because they offer remarkable dielectric and ferroelectric properties. Here, we demonstrate a powerful, nanoparticle-based deposition route towards BaTiO3 films with systematic thickness control over a wide range up to several microns. The unusual control over the film thickness with the maintenance of crack free nanostructures, phase and ferroelectric properties of the BaTiO3 films allows us to fabricate various future devices of different thicknesses by a single deposition method. For this, films are deposited from stable dispersions of BaTiO3 nanocrystals, synthesized via an efficient microwave-assisted non-aqueous sol–gel approach. Crack-free films of controlled thickness are obtained by a carefully elaborated, alternating process of spin-coating and intermediate drying. According to X-ray diffraction and confocal Raman microscopy, the final, sintered films consist of BaTiO3 nanocrystals of about 20 nm in a hexagonal–tetragonal phase mixture. The nanoparticulate films display outstanding optical characteristics exceeding 90% transparency above 500 nm and a band gap of 3.5 eV. The latter, band gap, is larger than the classic bulk material's band gap of 3.2 eV, indicating a more electrically insulating nature of the films. Piezoresponse force microscopy gives evidence for potent ferroelectric switching. This newly accessible film processing route with wide film thickness tuning allows for desired ferroelectric response with the advantage of a wide film thickness to implicate building blocks for various applications e.g. ferroelectric random access memory devices, microelectromechanical system devices or Bragg reflectors.

Authors contributing to RSC publications (journal articles, books or book chapters)
do not need to formally request permission to reproduce material contained in this
article provided that the correct acknowledgement is given with the reproduced material.

Reproduced material should be attributed as follows:

For reproduction of material from NJC:
Reproduced from Ref. XX with permission from the Centre National de la Recherche
Scientifique (CNRS) and The Royal Society of Chemistry.

For reproduction of material from PCCP:
Reproduced from Ref. XX with permission from the PCCP Owner Societies.

For reproduction of material from PPS:
Reproduced from Ref. XX with permission from the European Society for Photobiology,
the European Photochemistry Association, and The Royal Society of Chemistry.

For reproduction of material from all other RSC journals and books:
Reproduced from Ref. XX with permission from The Royal Society of Chemistry.

If the material has been adapted instead of reproduced from the original RSC publication
"Reproduced from" can be substituted with "Adapted from".

In all cases the Ref. XX is the XXth reference in the list of references.

If you are the author of this article you do not need to formally request permission
to reproduce figures, diagrams etc. contained in this article in third party publications
or in a thesis or dissertation provided that the correct acknowledgement is given
with the reproduced material.

Reproduced material should be attributed as follows:

For reproduction of material from NJC:
[Original citation] - Reproduced by permission of The Royal Society of Chemistry (RSC) on behalf of the
Centre National de la Recherche Scientifique (CNRS) and the RSC

For reproduction of material from PCCP:
[Original citation] - Reproduced by permission of the PCCP Owner Societies

For reproduction of material from PPS:
[Original citation] - Reproduced by permission of The Royal Society of Chemistry (RSC) on behalf of the
European Society for Photobiology, the European Photochemistry Association, and
RSC

For reproduction of material from all other RSC journals:
[Original citation] - Reproduced by permission of The Royal Society of Chemistry

If you are the author of this article you still need to obtain permission to reproduce
the whole article in a third party publication with the exception of reproduction
of the whole article in a thesis or dissertation.

Information about reproducing material from RSC articles with different licences
is available on our Permission Requests page.